Additional Information

NL, Industries, Inc. ("NL") directly holds 48,943,049 shares of common stock,
par value $0.01 per share ("Common Stock"), of the issuer constituting all of
the outstanding shares of Common Stock.

Valhi, Inc. ("Valhi") and Tremont LLC ("Tremont") are the direct holders of
approximately 63.1% and 21.4%, respectively, of the outstanding common stock
of NL.  Valhi is the direct holder of 100% of the membership interests of
Tremont.  Valhi Group, Inc. ("VGI"), National City Lines, Inc. ("National"),
Contran, the Harold Simmons Foundation, Inc. (the "Foundation"), the Contran
Deferred Compensation Trust No. 2 (the "CDCT No. 2") and The Combined Master
Retirement Trust (the "CMRT") are the direct holders of approximately 77.6%,
9.1%, 3.1%, 1.3%, 0.4% and 0.1%, respectively, of the outstanding shares of
Valhi common stock.  National, NOA, Inc. ("NOA") and Dixie Holding Company
("Dixie Holding") are the direct holders of approximately 73.3%, 11.4% and
15.3%, respectively, of the outstanding common stock of VGI.  Contran and NOA
are the direct holders of approximately 85.7% and 14.3%, respectively, of the
outstanding common stock of National.  Contran and Southwest Louisiana Land
Company, Inc. ("Southwest") are the direct holders of approximately 48.9% and
51.1%, respectively, of the outstanding common stock of NOA.  Dixie Rice
Agricultural Corporation, Inc. ("Dixie Rice") is the direct holder of 100% of
the outstanding common stock of Dixie Holding.  Contran is the holder of 100%
of the outstanding common stock of Dixie Rice and approximately 88.9% of the
outstanding common stock of Southwest.

Substantially all of Contran's outstanding voting stock is held by trusts
established for the benefit of certain children and grandchildren of Harold
C. Simmons (the "Trusts"), of which Mr. Simmons is the sole trustee.  As sole
trustee of each of the Trusts, Mr. Simmons has the power to vote and direct
the disposition of the shares of Contran stock held by each of the Trusts.

Harold C. Simmons is the chairman of the board and chief executive officer of
each of the issuer and NL and the chairman of the board of each of Tremont,
Valhi, VGI, National, NOA, Dixie Holding, Dixie Rice, Southwest and Contran.

The Foundation directly holds approximately 1.3% of the outstanding shares of
Valhi common stock.  The Foundation is a tax-exempt foundation organized for
charitable purposes.  Harold C. Simmons is the chairman of the board of the
Foundation.

The CDCT No. 2 directly holds approximately 0.4% of the outstanding shares of
Valhi common stock.  U.S. Bank National Association serves as the trustee of
the CDCT No. 2.  Contran established the CDCT No. 2 as an irrevocable "rabbi
trust" to assist Contran in meeting certain deferred compensation obligations
that it owes to Harold C. Simmons.  If the CDCT No. 2 assets are insufficient
to satisfy such obligations, Contran is obligated to satisfy the balance of
such obligations as they come due.  Pursuant to the terms of the CDCT No. 2,
Contran (i) retains the power to vote the shares of Valhi common stock held
directly by the CDCT No. 2, (ii) retains dispositive power over such shares
and (iii) may be deemed the indirect beneficial owner of such shares.

The CMRT directly holds approximately 0.1% of the outstanding shares of Valhi
common stock.  Valhi established the CMRT to permit the collective investment
by master trusts that maintain the assets of certain employee benefit plans
Valhi and related companies adopt.  Harold C. Simmons is the sole trustee of
the CMRT and a member of the trust investment committee for the CMRT.
Valhi's board of directors selects the trustee and members of the trust
investment committee for the CMRT.  Harold C. Simmons disclaims beneficial
ownership of the shares of Valhi common stock held by the CMRT, except to the
extent of his individual vested beneficial interest, if any, in the assets
held by the CMRT.

By virtue of the holding of the offices, the stock ownership and his services
as trustee, all as described above, (a) Harold C. Simmons may be deemed to
control such entities and (b) Mr. Simmons and certain of such entities may be
deemed to possess indirect beneficial ownership of shares directly held by
certain of such other entities.  However, Mr. Simmons disclaims such
beneficial ownership of the shares beneficially owned directly or indirectly
by any of such entities, except to the extent of his vested beneficial
interest, if any, in shares held by the CMRT and his interest as a
beneficiary of the CDCT No. 2.  Mr. Harold Simmons disclaims beneficial
ownership of all shares of Common Stock that NL directly holds.

Harold C. Simmons' spouse is the direct owner of 69,475 shares of NL common
stock.  Mr. Simmons may be deemed to share indirect beneficial ownership of
such shares.  Mr. Simmons disclaims all such beneficial ownership.

Valmont Insurance Company ("Valmont"), NL and a subsidiary of NL directly own
1,000,000, 3,522,967 and 1,186,200 shares of Valhi common stock,
respectively. Valhi is the direct holder of 100% of the outstanding common
stock of Valmont.  Pursuant to Delaware law, Valhi treats the shares of Valhi
common stock that Valmont, NL, and the subsidiary of NL own as treasury stock
for voting purposes.  For the purposes of the percentage calculations herein,
such shares are not deemed outstanding.